Introduction: Incidence of clinically evident abdominal wall trocar site hernias is known to be between 0.5 to 2% depending on type of surgery, port size, and type of port. The vast majority of these hernias occur at trocar sites of 10 mm or larger; thus many authors recommend routine closure of these defects. To our knowledge there is no study in the literature characterizing abdominal wall defects on computed tomography (CT) scans after laparoscopic roux-en-Y gastric bypass (LRNYGBP).

Methods: A retrospective chart review was performed of all patients undergoing LRNYGBP between 2005 and 2010 at one institution who had undergone a CT scan of the abdomen postoperatively for any reason. Port sites are in the upper abdomen as the surgeon stands between the legs of the patient. Dilating trocars were used for all cases (Endopath Xcel, Ethicon, Cincinnati, OH) It is our practice not to close any defect in the fascia which includes one 11mm port, two 12mm ports, one 5mm port, and a 5mm puncture for a liver retractor. Patients were excluded if they had undergone any abdominal surgery other than the LRNYGB prior to the CT scan. Records were searched for evidence of incisional hernia existence or repair. The location and the size of the defects seen on CT scan were documented.

Results: 828 LRNYGBP were performed. Of these, 152 patients had CT scans for review for a total of 456 trocar sites from 11 – 12mm ports. The mean age of the population was 44 years (range: 22 to 67). The mean weight was 288 pounds (range: 187 to 428) and the mean body mass index was 48 (range: 35.2 to 64). The population was mostly female (87%) and Caucasian (89%). The mean time from the day of surgery to CT scan was 350 days (range: 1 day to 1836 days). On review of the CT scans only two defects (0.4%) were identified in two separate patients (1.3%). One had an early symptomatic trocar site hernia requiring re-operation on postoperative day 6 suggesting a technical issue. The second was noted to have a 6 mm defect in the posterior fascia without an associated hernia. Interestingly there were no persistent abdominal wall defects noted on the 58 patients who had CT scans done within the first 30 days and the 39 patients underwent CT scan within the first week of bypass. Incidentally 34% of patients were noted to have umbilical hernias.

Conclusion: Trocar site hernias and persistent defects in the fascia are low after LRNYGB. This phenomenon may be partly due to rapid weight loss in the immediate pre- and postoperative periods. Additionally the absence of defects on CT seen within the first month of the bypass suggests the presence of different mechanisms like shearing forces (shutter mechanism) assisting with early closure of these trocar site defects. Our data suggest that routine closure of non-bladed trocar sites in the upper abdomen up to 12mm for bariatric surgery is not necessary.